The present invention relates to a vessel for refractory use or, more particularly, to a refractory vessel such as a crucible, boat, tube and the like capable of prolongedly withstanding extremely high temperatures frequently encountered in various processing procedures.
As is well known, progress of technologies in recent years results in a great increase of the kinds of processing procedures performed under extremely high temperatures. For example, various kinds of highly refractory materials, such as metals, metal compounds, glasses, ceramics and the like, are sometimes melted at the respective high melting points for the purpose of fabrication. The manufacturing process of semiconductor devices sometimes include a step in which certain materials such as gallium, arsenic, indium, aluminum and the like are melted in boat and vaporized. Further, many of single crystal materials used in electronic technologies, such as the so-called III-V compound semiconductors, e.g. gallium arsenide, gallium phosphide and indium phosphide, are manufactured by the Czochralski method for single crystal growing in whcih the starting materials are melted in a crucible.
Needless to say, one of the important factors having influences on the costs of these high-temperature processes is the durability or serviceable life of the vessel, e.g. crucibles, boats, tubes and the like, used in the process. Namely, it is usual that the vessel is used repeatedly in several runs until the vessel is broken or destroyed by the thermal stress. None of the conventional vessels are satisfactory in this regard since they are sometimes prematurely destroyed by the thermal shock in cooling or repeated heating cycles between room temperature and the high processing temperature. Often, they break after a continued use for a relatively short length of time or repeated use only in a few runs of an unpredictable number. Accordingly, it has been eagerly desired to have such refractory vessels capable of withstanding a prolonged use or a large number of repeated runs of use.